bug: built-in function .name own-property returns undefined (function foo(){}; foo.name === undefined)

[proggeramlug]

Summary

Accessor (getter/setter) properties on built-in prototypes are not reflectable: Object.getOwnPropertyDescriptor(%TypedArray%.prototype, "length") returns undefined, where the spec defines length, byteLength, byteOffset, and buffer as accessor properties with a get. User-defined accessors round-trip correctly, so the descriptor machinery works — built-in accessors just aren't modeled as real accessor properties.

Repro

var TAp = Object.getPrototypeOf(Int8Array.prototype);   // %TypedArray%.prototype
var d = Object.getOwnPropertyDescriptor(TAp, "length");
console.log(d && Object.keys(d).sort().join(","), "| get:", d && typeof d.get);
// Node:  "configurable,enumerable,get,set" | get: function
// Perry: "(undefined desc)"                | get: undefined

// (control) user-defined accessor works in BOTH:
var o = {}; Object.defineProperty(o, "p", { get(){ return 42; }, configurable:true, enumerable:true });
console.log(o.p, Object.getOwnPropertyDescriptor(o, "p").get && "has-get"); // 42 has-get  (both)

Why it matters

This is the Cannot read properties of undefined (reading 'get') cascade (16× in the built-ins/TypedArray sample) and contributes to TypedArray being ~1% in the #799 baseline. Any test that introspects a built-in getter via getOwnPropertyDescriptor(...).get fails.

Likely cause

length/byteLength/etc. on TypedArray (and presumably other built-in getters) are computed via codegen special-cases rather than installed as real accessor properties on the prototype, so reflection can't see them. Same root theme as the Function.prototype.call / builtin-prototype-method gaps: built-in members aren't reified as real properties.

Surfaced by the #799 Test262 radar. Part of #793.